| either of two herpes diseases caused by a herpesvirus that infects humans and some other animals and produces small, transient blisters on the skin or mucous membranes, one type of virus (herpes simplex virus type 1, or HSV-1) usually associated with oral herpes but also causing genital herpes and the other (herpes simplex virus type 2, or HSV-2) usually causing genital herpes. |

herpes simplex herpes sim·plex (sĭm'plěks')
n.
A recurrent viral disease that is caused by herpesvirus type one and is marked by fluid-containing vesicles on the mouth, lips, or face; cold sore.
A recurrent viral disease that is caused by herpesvirus type two and is marked by fluid-containing vesicles on the genitals.